1. Field of the Invention
The present invention relates to a separating method and device for separating a shaped section from a waste section during the manufacture of paper products, such as cases or containers made of paperboard or corrugated cardboard boxes.
2. Description of the Related Art
In general, paper products (the shaped sections) are manufactured by first forming folds in a paper sheet, the cutting slits between the shaped sections and the waste sections in the paper sheet (paperboard), leaving some connecting portions, by means of an automatic stamping machine.
Subsequently, a plurality of, for example, 50 sheets of this paper are carried on a female die on a separating device and the shaped sections are separated from the waste sections by pressing the shaped sections by means of a male die to cut the remaining connecting portions and accommodate the shaped sections to an accumulating device.
However, since the male die, consisting of an array of a large number of pins, and the female die, formed by a metal mold, and so on, are formed so as to have nearly the same shape and the same size as the shaped section, the male die and the female die should be replaced whenever the shape (pattern) of the paper product changes.
Heretofore, every time the pattern of the products is changed, the female die is replaced and mounting and dismounting operations on the pins (hereinafter called "pin registering operations") have been carried out.
In the conventional separating device, every time the pattern of the products changes, the female die must be replaced and the pin registering operations should be carried out.
In these operations, the number of pins is large and the pins must be disposed precisely along the contour of the shaped products, and so the operations are troublesome and require a long time.
As a result, the operations of the machine must be interrupted for a long period and hence the working efficiency of the machine is low.
Moreover, in the case where the number of products having the same shape is small, the number of times of use of each die is also small and hence the operations may be economically unprofitable.
Then, to solve the above-described problem, the inventor of the present invention adopts a method simultaneously forming an upper die complementary with a lower die by cutting a piece of plywood by means of a laser beam so that it conforms to the pattern of a shaped section of a paper sheet, and fastening the lower die to a lower die supporting part and the upper die to an upper die mounted in facing relation to lower die (Japanese Patent Examined Publication No. 60-108299, EPO0146158).
In the conventional device, although an economical die can be obtained, there are the following problems.
When a plurality of, for example, 50 sheets of paper are carried on the female die and the shaped sections are pressed by the upper die, the lower female die which may be made of plywood whose strength is low may break.
Since a boundary portion in the waste section between the shaped sections is especially narrow to prevent waste of paper sheet, the boundary portion of the lower die corresponding to the boundary portion in the waste section is very narrow compared to the other parts.
As a result, this boundary portion is in a very fragile condition.
Hereupon, a method of reinforcing the lower die by piling up the supporting plates on the lower face of the die can be considered to solve the above-described problem.
However, since the lower die is supported by the supporting plates, the shaped sections are prevented from falling through the supporting plates when the shaped section of the paper sheet is separated from the waste section.
Consequently, a thickness of the lower die, for example, paper sheets of only 30 mm can be separated. Therefore, it is impossible to separate paper sheets which become thicker than the thickness of the lower die after piling up, for example, 50 to 100 paper sheets, into the shaped section and the waste section by once.
In addition, since first the female die is fastened to the lower die supporting block after separating the male die from the female die and the male die is fastened to the upside die mount with positioning of the male die to the female die at the time that the male die and the female die are set in the separating device, a long time is required for the mounting operation and the operations may be economically unprofitable.
Furthermore, since many paper sheets, for example, 50 sheets are heavy and bulky, it is difficult for one operator to mount them on the lower die at once.
Hereupon, since the paper sheets are divided into a plurality of sheets, for example, 5 sheets, and the paper sheets are set on the lower die by positioning the shaped section and the female die by a plurality of operators, much labor and time are required to set specified sheets of paper.
Moreover, the stamping operation is sometimes interrupted by slippage of the positional relationship between the two dies.
In addition, since this setting operation of the paper sheet (hereinafter called "feeding operation") is difficult to perform because it is performed in the small stamping part, more and more the time for the feeding operation is required.